Network device and a method for networking

ABSTRACT

A networking device including a plurality of client ports arranged for communicating with a plurality of clients, a service port arranged for communicating with a machine arranged to communicate with the plurality of clients, and networking componentry arranged to communicate electromagnetic communications between the plurality of client ports and the service port.

RELATED APPLICATIONS

The present application is continuation of U.S. patent application Ser.No. 14/385,121, filed Sep. 12, 2014, which is a National Phase entry ofPCT Application No. PCT/AU2012/000410, filed Apr. 19, 2012, which claimspriority from Australian Patent Application No. 2012900975, filed Mar.12, 2012, the disclosures of which are hereby incorporated by referenceherein in their entirety.

TECHNICAL FIELD

The disclosure herein generally relates to a network device and a methodfor networking, and particularly but not exclusively to low latencycommunication between a plurality of client ports and a service port ofthe network device.

BACKGROUND

The latency of a communication sent between one of the plurality ofclients and a server may be, in some circumstances, an important factorin securing a favorable outcome. For example, being the first to have acomplete electronic trade order received by a stock exchange mayestablish trade priority. Advantage can then be taken of favorableprices for financial instruments, examples of which include but are notlimited to shares, derivatives and futures. Being the first to receivemarket information may enable a trader to take advantage of favorablemarket conditions before others. In another example, a favorable outcomefor an individual playing a networked electronic game may be determinanton the latency of a gaming command received by a gaming system. Beingable to send a low latency instruction to place a wager or a bid at anauction, for example, may increase the probability of securing goododds, a good price, or a successful purchase. Furthermore, it may bedesirable, in at least some circumstances, to keep communicationsconfidential.

SUMMARY

Disclosed herein is a network device. The network device comprises aplurality of client ports arranged for communicating with a plurality ofclients. The network device comprises a service port arranged forcommunicating with a machine arranged to communicate with the pluralityof clients. The network device comprises networking componentry arrangedto communicate electromagnetic communications between the plurality ofclient ports and the service port.

In an embodiment, the networking componentry comprises a unidirectionalnetwork arranged to unidirectionally communicate an electromagneticcommunication received by any one of the plurality of client ports tothe service port. The unidirectional network may comprise a plurality ofclient port receivers. Each of the plurality of client ports may have arespective one of the client port receivers. The unidirectional networkmay comprise a multiway switch arranged to control which one of theplurality of client port receivers is in communication with the serviceport. The multiway switch may comprise a 1-pole multiway (1×N) switch.The 1 pole of the multiway switch may be in communication with theservice port. The service port may comprise a service port transmitterin communication with the 1-pole of the multiway switch. Each way of themultiway switch may be in communication with only one of the pluralityof client port receivers at a time. The unidirectional network maycomprise a plurality of client port buffers. Each of the plurality ofclient port buffers may be electromagnetically disposed between arespective one of the plurality of client port receivers and themultiway switch. Each of the client port buffers may be arranged toexclusively cooperate with the respective one of the plurality of clientport receivers. Embodiments in which a respective one of the client portbuffers is dedicated to each of the plurality of client port receiversmay have less latency than embodiments in which the more than one clientport receiver share a buffer. The networking componentry may comprise ascheduler arranged to control which way of the multiway switch isconnected to the 1 pole. The scheduler may be in communication with theplurality of client ports. The scheduler may be a first-in-first-outscheduler.

In an embodiment, the networking componentry comprises anotherunidirectional network arranged to communicate another electromagneticcommunication received by the service port to at least one of theplurality of client ports. The other electromagnetic information maycomprise, for example, market information. The other unidirectionalnetwork may comprise a common bus. The common bus may beelectromagnetically disposed between the plurality of client ports andthe service port. The other unidirectional network may comprise aplurality of client port transmitters. Each of the plurality of clientports may have a respective one of the client port transmitters. Thecommon bus may be arranged to broadcast the other electromagneticcommunication from the service port at the plurality of client porttransmitters. The other unidirectional network may comprise a serviceport buffer. The service port buffer may be electromagnetically disposedbetween a service port receiver and the common bus.

In an embodiment, the networking device comprises a communicationcontrol system arranged to send via one of the plurality of client portsa command to at least one of pause and stop transmission to thenetworking device. The communication control system may be arranged tosend the command when the device is approaching capacity. The commandmay be sent to prevent information loss. The networking device maycomprise another communication control system arranged to send via theservice port another command to at least one of pause and stoptransmission to the networking device. The other communication controlsystem may be arranged to send the command when the device isapproaching capacity. The command may be sent to prevent informationloss.

Embodiments having a unidirectional network and another unidirectionalnetwork may provide an ingenuous approach to providing low latencycommunications. Complicated N×N switching may be not necessary, andpower consumption and complexity may be reduced.

In an embodiment, the scheduler and the multiway switch are synchronizedby a clock signal. Additionally, the plurality of client porttransmitters may be synchronized by the clock signal. Additionally, theservice port transmitter may be synchronized by the clock signal. Havingthe scheduler, service port transmitter, multiway switch and theplurality of client port transmitters, for example, synchronized mayreduce or remove altogether the need for buffers (that may add latency)that would otherwise be needed if an electromagnetic communicationsreceived at a client port travelled from one part of the networkingdevice to another having a different clock rate.

In an embodiment, the networking componentry is arranged to blockelectromagnetic communications between the plurality of client ports.The client port receiver of any one of the client ports may beelectromagnetically isolated from the client port transmitter of any ofthe other client ports. Consequently, confidentiality of clientcommunications may be achieved.

Generally, but not necessarily, the electromagnetic communicationcomprises a packet. Generally, but not necessarily, the otherelectromagnetic communication comprises another packet. The packet andthe other packet may each comprise, for example, a header and a payload.At least one of the packet and the other packet may comprise and atrailer. The packet and the other packet may comprise, for example, aninternet protocol (IP) packet. The internet protocol packet may have aTCP segment payload, for example.

In an embodiment, the networking componentry is arranged to associatefilter information with each of the plurality of client ports. Thenetworking componentry may be arranged to communicate the otherelectromagnetic communication received by the service port to those ofthe plurality of client ports that have associated filter informationindicated by the electromagnetic message. The networking componentry maybe arranged to extract filter information from the other electromagneticmessage. The information may be extracted from at least one of a header(that is, “header information”), a payload (“payload information”) and atrailer (“trailer information”) of the other electromagneticcommunication. The networking componentry may be arranged to compare theextracted filter information with the filter information associated withthe ports. Each of the plurality of client ports may have associatedfilter information stored thereat. The filter information may comprise,for example, at least one of a MAC address, an Internet Protocol (IP)address, IP packet header and/or trailer information, TransmissionControl Protocol (TCP) port identification information, and UserDatagram Protocol (UDP) port identification information. Generally, anysuitable filter information may be used.

In an embodiment, the networking componentry comprises a plurality ofelectromagnetic communication filters that each have associated filterinformation. Each of the plurality of client ports may be operativelycoupled to at least one of the plurality of electromagneticcommunication filters. Each of the plurality of electromagneticcommunication filters may be at a respective one of the plurality ofclient ports. The plurality of electromagnetic communication filters maybe arranged to communicate the other electromagnetic communicationreceived by the service port to only those of the plurality of clientports that have associated filter information indicated by the otherelectromagnetic communication. The plurality of electromagneticcommunication filters may each comprise at least one of a Media AccessControl (MAC) filter, an Internet protocol (IP) filter, an IP portfilter, a TCP port filter, a UDP port filer, a header informationfilter, a payload information filter and a trailer information filter.Generally, the electromagnetic filters may comprise any filter suitablefor the type of filtering being performed.

In an embodiment, the networking componentry associates with at leastsome of the plurality of client ports filter information unique to eachof the at least some of the plurality of client ports. That is, thefiltering information may be associated for unicasting the otherelectromagnetic message received by the service port. The networkingcomponentry may associate filter information with more than one of theplurality of client ports that is the same for each of the more than oneof the plurality of client ports. That is, the filtering information maybe associated for at least one of multicasting and broadcasting theother electromagnetic communication received by the service port.

In an embodiment, the networking componentry comprises electronics. Theunidirectional network and the other unidirectional network may eachcomprise a respective electrical network. The networking componentry maycomprise at least one logic device. The at least one logic device maycomprise a programmable logic device. Examples of programmable logicdevices include but are not limited to a field programmable gate array(FPGA) and a complex programmable logic device. Alternatively oradditionally, the at least one logic device may comprise an applicationspecific integrated circuit (ASIC). At least one of the unidirectionalnetwork and the other unidirectional network may at least in part beintegral to the at least one logic device. The multiway switch may beintegral to the at least one logic device. The plurality of client portbuffers and the service port buffer may be integral to the at least onelogic device. The plurality of electromagnetic message filters may beintegral to the at least one logic device. The scheduler may be integralto the at least one logic device.

An embodiment may comprise electronics arranged for connecting with awireless network.

In an embodiment, the networking componentry comprises optics. Thefilter information may comprise optical wavelength information. Forexample, at least some of the electromagnetic filters may be opticalbandpass filters comprising Bragg fiber gratings and/or dielectric stackfilters. The multiway switch may comprise an optical switch, such as amicroelectromechanical system (MEMS) optical switch or an optoelectronicswitch.

In an embodiment, the networking componentry comprises optoelectronics.For example, the network device may connect to an optical fiber. Thereceiver and the transmitter may be an optical receiver and an opticaltransmitter respectively. The plurality of client port receivers and theplurality of client port transmitters may comprise optical receivers andoptical transmitters respectively.

Disclosed herein is a method for networking. The method comprises thestep of communicating electromagnetic communications between a pluralityof client ports arranged for communication with a plurality of clientsand a service port arranged for communication with a machine arranged tocommunicate with the plurality of clients.

An embodiment of the method comprises the step of blockingelectromagnetic communications between the plurality of client ports.

An embodiment of the method comprises the step of communicating anelectromagnetic communication received by any one of the plurality ofclient ports via a unidirectional network to the service port. Themethod may comprise the step of controlling which one of the pluralityof client ports is in communication with the service port. The methodmay comprise the step of scheduling the order in which the plurality ofclient ports are in communication with the service port. The schedulingmay be first-in-first-out scheduling. The method may comprise the stepof buffering the electromagnetic communication. The method may comprisethe step of each of a plurality of client port buffers exclusivelycooperating with the respective one of a plurality of client portreceivers.

In an embodiment, the method may comprise the step of communicatinganother electromagnetic communication received by the service port to atleast one of the plurality of client ports via another unidirectionalnetwork. The step of communicating the other electromagneticcommunications via the other unidirectional network may comprise thestep of broadcasting the other electromagnetic communication. The methodmay comprise buffering the other electromagnetic communication.

In an embodiment, the method comprises the step of synchronizing thestep of controlling and the step of scheduling to a clock signal.Additionally, the method may comprise the step of synchronizing sendingof the electromagnetic communication from the service port to the clocksignal. Additionally, the method may comprise the step of synchronizingsending of the other electromagnetic communication from any one of theplurality of client ports to the clock signal.

In an embodiment, the method comprises the step of communicating theother electromagnetic communication received by the service port tothose of the plurality of client ports that have associated filterinformation indicated by the electromagnetic message.

In an embodiment, the method may comprise the step of associating filterinformation with each of the plurality of client ports. The method maycomprise the step of associating with each of the plurality of clientports information unique to each of the plurality of client ports. Themethod may comprise the step of associating identical filter informationwith more than one of the plurality of client ports. The method maycomprise the step of extracting filter data indicative of filterinformation from the other electromagnetic communication. The method maycomprise the step of comparing the filter data extracted from the otherelectromagnetic communication with filter information associated withthe ports.

In an embodiment, the method comprises the step of sending via one ofthe plurality of client ports a command to at least one of pause andstop transmission. The command may be sent when a capacity isapproached. The command may be sent to prevent information loss.Similarly, the method may comprise sending via the service port acommand to at least one of pause and stop transmission.

Disclosed herein is processor readable tangible media including programinstructions which when executed by a processor causes the processor toexecute the method as disclosed above.

The tangible media may comprise, for example, a hard drive, FLASHmemory, or any other suitable tangible media.

Disclosed herein is a program for instructing a processor, which whenexecuted by the processor causes the processor to execute the method asdisclosed above.

Any one or more features of the network device, the method fornetworking, the processor readable tangible media, and the programdisclosed above may be combined with any one of more feature of themethod disclosed above.

BRIEF DESCRIPTION OF THE FIGURES

Embodiments of a networking device and a method for networking will nowbe described by way of example only with reference to the accompanyingfigures, in which:

FIG. 1 shows a schematic plain view of one embodiment of a networkingdevice;

FIG. 2 shows a block diagram illustrating networking componentry of thedevice;

FIG. 3 shows a unidirectional network within the networking componentry;and

FIG. 4 shows another unidirectional network within the networkingcomponentry.

DESCRIPTION OF EMBODIMENTS

FIG. 1 shows a schematic plain view of one embodiment of a networkingdevice generally indicated by the numeral 10. The device 10 is arrangedto communicate with a plurality of clients. The clients may be in theform of financial instrument transaction ordering computers, forexample. The networking device 10 may also be arranged to communicatewith a machine in the form of a server, for example. The server may be,for example, in a stock exchange and executes orders for the buying andselling of financial instruments originating from the clients.

This embodiment of the networking device 10 has a multilayer printedcircuit board 12 having components mounted thereto which generally, butnot necessarily, are connected to each other by conductive pathways,which may comprise, for example, tracks, signal traces, strip linesand/or micro strip lines, and wires, as appropriate. Generally, but notnecessarily, the printed circuit board 12 is housed by a rack mountableenclosure having dimensions of 1 rack unit, although any suitableenclosure may be used or not used as desired. The printed circuit boardhas various surface mounted and/or through hole components mountedthereto.

A mains supply 14 may be mounted to the printed circuit board 12, themain supply in use producing a relatively low voltage, such as 12, 24 or48 volts as suitable, from a relatively high voltage source, forexample, a 110V or 240V electricity grid. There may be a DC regulator inthe form of a switched mode power supply module 15 mounted to theprinted circuit board 12 that receives the low voltage output from themains supply 14 and powers two or more active conductive rails integralto the circuit board 12. Alternatively, the mains supply and DCregulator may be mounted within the enclosure separate from the printedcircuit board 12.

At least one fan 16 may be mounted to the circuit board 12 oralternatively the enclosure. The at least one fan may provide airflowacross the multilayer printed circuit board to extract waste heat.

The printed circuit board 12 may also have mounted thereto a managementunit 19 comprising, in this but not necessarily all embodiments, an ARMprocessor communicating with serial or Ethernet interfaces 23 forreceiving instructions via an Ethernet (or other) management network orother source, for example. The management unit 19 may also controlactive indicia 25 in the form of LED status lights mounted at the frontof the enclosure.

The embodiment of the network device 10 of FIG. 1 has a plurality ofports, for example port 17 and 27. Each of the ports has a physicallayer interface in the form of a transceiver, such as transceiver 18 ofport 17. In this embodiment, but not necessarily in all embodiments, theplurality of transceivers comprise Small Form Factor Pluggable Plus(SFP+) transceivers. Other embodiments may use GBIC, XFP, XAUItransceivers, or generally any suitable transceivers. Alternativeembodiments may use separate receivers and transmitters that are notintegral to transceivers. The transceivers 18 are arranged to engage oneor more received physical layer conduits in the form of external opticalfiber network cables and/or copper network cables. The transceiver maysend and receive electromagnetic communications in the form of at leastone of an optical signal and an electrical signal. In this embodiment,the transceivers are each configured to receive two LC connectorsterminating respective optical fiber cables that click into thetransceiver, but any suitable connectors may be used. One of the opticalfibers is for electromagnetic communications received by thetransceiver, and communicates with a receiver 42 of the transceiver, andthe other is for electromagnetic communications sent by the transceiverand is connected to a transmitter 44 of the transceiver. Thetransceivers generate electrical signals from the received opticalsignals, and subsequently communicate the electrical signals to theprinted circuit board 12. The transceivers may support the gigabitEthernet protocol and receive and/or transmit Ethernet packets, butother embodiments may have transceivers that support SONET, FibreChannel, or any other suitable communications standard.

In the embodiment of FIG. 1, but not necessarily in all embodiments, oneof the transceivers 29 in use receives a connector of an optical fibernetwork cable in communication with the machine arranged to communicatewith the plurality of clients. The port associated with this transceiver29 is the service port 27. Some of the remaining transceivers generallyindicated by the numerals 17 and 21 (in some embodiments all of theremaining transceivers) in use receive respective ends of optical fibercables in communication with at least a respective one of the pluralityof clients. These ports are client ports. The port 17 is one of theclient ports 21. In some embodiments more than one client is incommunication with one of the client ports.

The transceivers may be housed in enclosures in the form of SFP cages 20fixed to the printed circuit board 12. The cages provide an electricalconnection between electrical contacts on the transceivers 18 andconductive tracks 22 in the form of stripline and/or micro strip linetracks formed on or within the circuit board 12. The cages may also actas Faraday cages to reduce electromagnetic interference, and extractheat from the transceiver. In alternative embodiments, the transceiversmay be mounted directly to the printed circuit board.

The stripline 22 (which may be a micro-stripline, for example) providesa conduit for communications between the transceivers and networkingcomponentry 24. The networking componentry is arranged to communicateelectromagnetic communications between the plurality of client ports andthe service port. In this embodiment the networking componentry 24comprises a logic device 26 in the form of a field programmable gatearray (FPGA). In other embodiments, the logic device may be any suitablelogic device such as a complex programmable logic device, and anapplication-specific integrated circuit (ASIC). In some embodiments, thenetworking componentry may comprise more than one logic device.

The field programmable array 26 may have any suitable architecture. Inone embodiment, the FPGA architecture comprises an array of configurablelogic blocks, I/O heads or pins, and routing channels. Generally but notnecessarily, the logic blocks comprises of logical cells that maycomprise of, for example, a look up table, a full adder, and a D-typeflip flop. Clock signals may be routed through special purpose dedicatedclock networks within the FPGA in communication with a reference clock33 mounted on the printed circuit board 12. The FPGA may also includehigher-level functionality including embedded multipliers, genericdigital signal processing blocks, embedded processors, high-speed I/Ologic for communication with components external of the FPGA (forexample), and embedded memories that may be used by buffers.

The reference clock 33 has a frequency of 156.25 MHz, but otherfrequencies may be used as appropriate.

The internal structure of the FPGA is configured to form a plurality ofmodules. The modules are initially specified, for example, using ahardware description language, examples of which include HDL, VHDL andVERILOG. The functionality to be implemented in the FPGA is described ina hardware description language. The description is compiled,synthesized and mapped to the FPGA using appropriate EDA tools to aconfiguration file that, when loaded or programmed into the FPGA, causesthe FPGA to implement the functionality described.

Generally, but not necessarily, the electromagnetic communicationsprocessed by the networking device comprise packets. The packetsgenerally, but not necessarily, comprise, for example, a header, and apayload. The packets may also have a trailer. The electromagneticcommunications may be structured in accordance with the Open SystemsInterconnection Model, in which each payload may be itself anotherpacket of another layer of the OSI model. For example, at the physicallayer the packet is a collection of bits. The physical layer packet maycomprise a data link packet having a datalink header, a datalink payloadand a datalink trailer. The datalink payload may in turn comprise aNetwork data packet such as an IP packet. The FP packet payload maycomprise a TCP or UDP packet (“segment”). This layered structure maycontinue to the Application layer.

FIG. 2 shows a block diagram of the networking componentry 24 of thedevice 10. In this embodiment, the networking componentry comprises aplurality of modules integral with the field programmable array 26 orother logic device. The network componentry 24 is in communication withthe plurality of transceivers 21 at the client ports via strip lines 22,for example. The networking componentry 24 is also in communication withthe transceiver 29 of the service port 27.

In alternative embodiments, one or more of the modules shown as beingintegral with the field programmable field array 26 may in fact be notso integrated, or components not shown to be integral may in fact bewholly or partially integrated. For example, receive (Rx) Media AccessControl (MAC) module 28 and the transmit (Tx) MAC module 30 may comprisededicated hardware modules mounted to the printed circuit board 12. Someof the modules may be partially implemented on the FPGA, and partiallyon other components mounted on the circuit board. For example, the Rxand Tx MAC modules may have a preprocessing sub module off the FPGA 26and a further processing sub module integral with the FPGA. In oneembodiment the device 10 is connected to a communications cable thatcarries electrical Ethernet packets, and the electrical Ethernet packetsmay be communicated directly to a high speed input of the FPGA via astrip line, for example. In these embodiments, the transceivers and MACmodules may respectively comprise transceiver modules and MAC modulesintegral with the FPGA.

FIG. 3 shows a unidirectional network within the networking componentry.Most other modules of the networking componentry, and their connections,that are not part of the unidirectional network are hidden forexplanatory purposes only. The unidirectional network is arranged tocommunicate electromagnetic communications in the form of packets, forexample Ethernet packets, received by any one of the transceivers at theplurality of client ports 21 to the transceiver 26 at the service port27.

The unidirectional network also comprises a switch 34 in the form of a1-pole multiway switch (Nx1 switch) that can be operated toelectromagnetically connect any one of the client port receivers, suchas Rx PHY 42 and 52, with the service port transmitter 36. The 1 pole,indicated by the numeral 40, is in electrical communication with theservice port transceiver 29. The multiple ways, such as 48 and 50,(there are more than three ways in this embodiment) are each incommunication with a respective one of the receivers of the client ports21. In this embodiment, MAC modules, such as 28, are electromagneticallydisposed between the switch and the client port transceiver.

The unidirectional network also comprises a plurality of buffers, suchas buffers 31, in the form of first-in-first-out (FIFO) buffers. Buffer31, for example, is electromagnetically disposed between one of theplurality of client port receivers 21 and the multiway switch 34. The RxFIFO buffers combined may be regarded as a single buffer, in which casethe buffer is electromagnetically disposed between the plurality ofclient port receivers and the multiway switch. In this embodiment,electromagnetic communications received on different ones of theplurality of client port receivers are buffered with different clientport buffers. Each of the client port buffers are arranged, in this butnot necessarily all embodiments, to exclusively cooperate with arespective one of the plurality of client port receivers. Embodiments inwhich a respective one of the client port buffers is dedicated to eachof the plurality of client port receivers may have less latency thanembodiments in which the plurality of client port receivers share abuffer.

The networking componentry 24 has a scheduler 42. The scheduler 42determines the order in which the switch 34 connects with the pluralityof client port receivers 21. The scheduler 42 and the client port Rx MACmodules, such as 28, are in communication via an electrical conductor inthe form of strip lines 46. The client port Rx MAC modules are eacharranged to signal to the scheduler the arrival of electromagneticcommunications at their respective client ports. The signal may be, forexample, a one clock cycle logical 1. The scheduler comprises logicgates, and memory implementing a first-in-first-out (FIFO) buffer. Portidentification information is stored in the FIFO buffer in the orderthat signals are received from the client ports' Rx MACs. The schedulerexecutes a scheduling algorithm that is, in this embodiment, afirst-in-first out algorithm. Thus the messages are forwarded to theservice port in order of being received by the device 10. For example,if the scheduler 42 receives a signal from Rx MAC 46 then a signal fromRx MAC 28, then the scheduler will cause the switch 34 to connect way 48to the 1 pole to receive packets from receiver 52 and then, after thepackets from receiver 52 are received, connect way 50 to the 1 pole toreceive packets from receiver 42. Generally any suitable, schedulingalgorithm, such as a round robin algorithm, may be used. Electronicorder applications, such as electronic trading, may prefer FIFOscheduling. In the case that signals received from two or more Rx MACsare temporally indistinguishable, the scheduler may execute anotheralgorithm to determine which port has priority. For example, thealgorithm may be a round robin algorithm or arbitrarily give one of theports priority. Random port selection may also be used. The schedulermay also comprise packet collision handling.

FIG. 4 shows another unidirectional network within the networkingcomponentry. Most other modules of the networking componentry, and theirconnections, that are not part of the other unidirectional network arehidden for explanatory purposes only. The other unidirectional networkis arranged to communicate electromagnetic communications from theservice port 29 to the plurality of client ports 21. The otherunidirectional network comprises a common bus, generally indicated bythe numeral 54. The common bus is electromagnetically disposed betweenthe plurality of client ports 21 and the service port 29. The busbroadcasts any electromagnetic communications received by the serverport receiver (Rx PHY) 38 towards the plurality of client ports.

Many circumstances require that a message intended for a particularclient not reach any other client. This may be for confidentialitypurposes, for example. In the case that the networking device 10 is usedfor electronic trading, for example, the prices and quantitiesassociated with client orders must remain strictly confidential. Thenetworking componentry 24 is arranged to associate filter informationwith each of the plurality of client ports 21 and is arranged tocommunicate an electromagnetic communication received by the serviceport 29 to those of the plurality of client ports 21 that haveassociated filter information indicated by the electromagnetic message.In this but not necessarily in all embodiment, the filtering isperformed by client port transmit (Tx) MAC modules, for example thatindicated by the numeral 30. The client port transmit MAC modules areelectromagnetically disposed between a respective transmitter, forexample transmitter 44, and the common bus 54. The Tx MACs each have aninformation comparator arranged to extract filter information from theelectromagnetic message received via the service port receiver 38 andthen compare the extracted filter information with filter informationassociated with the ports. The information may be extracted from atleast one of a header, a payload and a trailer. If the extracted filterinformation matches filter information associated with a port then theTx MAC communicates the communication to the transmitter the Tx MAC isin communication with. In this embodiment, but not necessarily in allembodiments, the filter information is stored in memory within the TxMACs. The filter information comprises, in this embodiment, MAC addressinformation. Some alternative embodiments have filters that filter onthe basis of Internet protocol (IP) address information, or filters thatoperate on another Open Systems Interconnection (OSI) model layer, forexample the network or transport layers. The filters may comprise of atleast one of a MAC address filter, an IP filter, an IP port filter, aTCP port filter, and a UDP port filter, for example. IP address and portfiltering is logically part of layer 3 and layer 4 packet processingrespectively, above the layer that the MACs operate at (layer 2). Thefilters may comprise a header information filter, a payload informationfilter and a trailer information filter, for example.

The client port Tx MACs may incorporate any of these filters, oralternatively and/or additionally there may be additionalelectromagnetic communications filters, for example optional filtermodules 60 to 64 of FIG. 4. IP address filtering may be implemented byadditional IP filters that are in series the client port Rx MACs, forexample. The additional filters may be electrically disposed between thecommon bus and the Tx MACs, as for optional filter 63, or the Tx MACsand the Tx PHYs, as for optional filter 62 for example. This may,however, add latency to the receive path. Another implementation withpotentially lower latency has IP filters in parallel with the RX MACs,as for optional filter 60, where the IP address and port filters examinethe incoming data at the same time as the MAC.

Each of the plurality of client port receivers may beelectromagnetically isolated from a respective one of the plurality ofclient port transmitters. The embodiment of the networking device ofFIGS. 1 to 4 is so arranged.

In this embodiment, the networking componentry associates filterinformation that uniquely identifies each of the plurality of clientports. Consequently, it is possible for the server to send a messagewhich is received by only the intended client recipient. The networkingcomponentry is also able, in this embodiment at least, to associatefilter information with more than 1 client port. Consequently, theserver may send a message for broadcasting or multicasting and thenetworking device will comply.

The filters may be automatically configured during initialcommunications between the plurality of clients and the device. Themanagement unit may, however, be instructed via the serial, USB,Ethernet or other interfaces to configure the filters of the networkingcomponentry discussed above. The management unit is in communicationwith the FPGA or ASIC via tracks 13 for communication of instructionsand filter information.

In this embodiment of a networking device 10, but not necessarily allembodiments, the other unidirectional network has a first communicationcontrol system. Electromagnetic communications received by the serviceport receiver 38 and subsequently processed by the service port receive(Rx) MAC 58, may be stored in a service port buffer 32 in the form of afirst-in-first-out buffer. Buffering may be required if a client porttransmitter is not available because, for example, the respectiveconnected client has sent a stop or pause transmission command to thenetworking device, or a buffer is reaching capacity. Without thecommunication control system the received electromagnetic communicationsmay be partially or entirely discarded if the buffer is at capacity, forexample, which may be unacceptable in many circumstances. Generally, thefirst communication control system may prevent information overload ofthe networking device and thus prevent information loss.

The service port Tx MAC 56 is in communication with the service port RxFIFO 32. The Tx MAC 56 and the Rx FIFO 32 cooperate to control the flowof electromagnetic communications to the client port transmitterswithout information loss. In the case that the service port buffer 32 isat or approaching capacity, or an upper capacity threshold is reached,then the Rx FIFO 32 may instruct the Tx MAC 56 to cause the service porttransmitter 36 to send a stop or pause transmission command to theserver before information is lost because it can not be processed onreceipt. The command may be for the server to pause transmission forbetween 1 μs and 100 μs.

The upper capacity threshold and buffer size may be chosen in view ofthe time taken for the command to reach its destination. Once the bufferhas at least partially emptied or a lower capacity threshold reached,the Rx FIFO 32 may instruct the Tx MAC 56 to cause the service porttransmitter 36 to send a start transmission command that is subsequentlyreceived by the connected server.

In this embodiment of a networking device, but not necessarily for allembodiments, the unidirectional network has a second communicationcontrol system. The client port 18, as may the other client ports 21, isin communication with a client port buffer 31 in the form of afirst-in-first-out buffer. Electromagnetic communications received bythe client port receiver 42 may be stored in the buffer 31 if the switch34 does not connect respective way 50 with the 1-pole 40. When theswitch is operated to connect the respective way 50 to the pole 40,information stored in the buffer 31 may be transmitted via the switch 34to the client port Tx MAC 56 and then to the client port transmitter 36.The buffer 31 is arranged to, when it is approaching and/or at capacity,to send to the corresponding Tx MAC 30 an instruction to cause theclient port transmitter 44 to send a pause or stop transmission commandto the client connected to the respective port. Without the secondcommunication control system, the electromagnetic communicationsreceived by the client port transmitters may be partially or entirelydiscarded, which may be unacceptable in many circumstances. Generally,the second communication control system may prevent information overloadof the networking device and subsequent information loss.

Similarly, a stop or pause command received by the client port receiver42 from the connected client and communicated to the Rx MAC 28 willcause the Tx MAC 30 stop or pause transmission.

In the embodiment of FIGS. 1 to 4, the scheduler, the plurality ofclient port transmitters, the multiway switch, and the service porttransmitter are synchronized by a clock signal from the reference clock33. If electromagnetic signals within the network device traveled from afirst network device component to another network device componenthaving a different clock frequency than the other then a buffer would berequired. The buffer would introduce latency. Consequently, thisembodiment of a networking device may have relatively low latency.

While the network connections described above may comprise opticaland/or electrical Ethernet (10 Mb, 40 Mb, 1 Gb, 10 Gb, 40 Gb, 100 Gb,400 Gb, 1 Tb), it will be understood that other network types andprotocols may be used, such as INFINIBAND and WiFi. Generally, anypacket based protocol may be used. Alternatively or additionally, one ormore of the network connections may alternatively be a serial portconnection, a USB port connection, a Fire Wire™ port connection, aThunderBolt™ port connection, a PCI or PCIe connection, a SONET (or SDH)connection with or without a sonnet demultiplexing device, or generallyany suitable type of connection.

Generally, in the disclosure above, the term “electromagnetically” maybe replaced with “electrically” when required for embodiments that areprimarily electrical in nature. For example, a component within an ASICor FPGA may be electrically disposed between two other components in theASIC or FPGA.

Variations and/or modifications may be made to the embodiments describedwithout departing from the spirit or ambit of the invention. Forexample, the networking componentry may comprises optics. The filterinformation may comprise optical wavelength information. For example, atleast some of the electromagnetic filters may be optical bandpassfilters comprising Bragg fiber gratings and/or dielectric stack filters.The multiway switch may comprise an optical switch, such as amicroelectromechanical system (MEMS) optical switch or an optoelectronicswitch. Alternatively, the network connections may be wireless. Thenetworking device may modify the electromagnetic communication and otherelectromagnetic communication. The present embodiments are, therefore,to be considered in all respects as illustrative and not restrictive.

Prior art, if any, described herein is not to be taken as an admissionthat the prior art forms part of the common general knowledge in anyjurisdiction.

In the claims which follow and in the preceding description of theinvention, except where the context requires otherwise due to expresslanguage or necessary implication, the word “comprise” or variationssuch as “comprises” or “comprising” is used in an inclusive sense, thatis to specify the presence of the stated features but not to precludethe presence or addition of further features in various embodiments ofthe invention.

The invention claimed is:
 1. A network device comprising: a plurality ofclient ports arranged for communicating with a plurality of clients; aservice port arranged for communicating with a machine; and physicalnetwork componentry comprising: a reference clock; and a logic device,comprising: a scheduler for selecting a client port of the plurality ofclient ports based on an order of a plurality of electromagneticcommunications received by the plurality of client ports; and a multiwayswitch, configured by the scheduler to place the selected client port ofthe plurality of client ports in communication with the service port;wherein the multiway switch is interposed between the plurality ofclient ports and the service port; wherein electromagneticcommunications received from the selected client port are communicated,after configuration by the scheduler, via the multiway switch to themachine, wherein the plurality of client ports, the multiway switch, thescheduler, and the service port are synchronized by a clock signal fromthe reference clock.
 2. The network device of claim 1, wherein thenetworking componentry comprises a common bus.
 3. The network device of2, wherein the common bus is arranged to broadcast the plurality ofelectromagnetic communication from the service port to the plurality ofclient ports.
 4. The network device of claim 2, further comprising aservice port buffer that is electrically disposed between the serviceport and the common bus.
 5. The network device of claim 1, furthercomprising a plurality of client port transmitters, each of theplurality of client ports having a respective one of the plurality ofclient port transmitters.
 6. The network device of claim 1, furthercomprising a communication control system arranged to send via theservice port a command to at least one of pause and stop transmission tothe networking device to prevent information loss when the networkingdevice is approaching capacity.
 7. The network device of claim 1,wherein the logic device is a field programmable gate array (FPGA). 8.The network device of claim 1, wherein the networking componentry isarranged to associate filter information with each of the plurality ofclient ports, and arranged to communicate each of the plurality ofelectromagnetic communications received by the service port to those ofthe plurality of client ports that have associated filter informationindicated by the electromagnetic communication.
 9. The network device ofclaim 8, wherein the networking componentry is arranged to extractfilter information from the plurality of electromagnetic communications.10. The network device of claim 9, wherein the networking componentry isarranged to compare the extracted filter information with the filterinformation associated with the plurality of client ports.
 11. Thenetwork device of claim 8, wherein each of the plurality of client portsmay have associated filter information stored thereat.
 12. The networkdevice of claim 8, wherein the filter information comprises at least oneof a MAC address, an Internet Protocol (IP) address, IP portidentification information, Transmission Control Protocol (TCP) portidentification information, and User Datagram Protocol (UDP) portidentification information.
 13. The network device of claim 8, whereinthe networking componentry comprises a plurality of electromagneticcommunication filters that each have associated filter information. 14.The network device of claim 13, wherein each of the plurality of clientports is operatively coupled to at least one of the plurality ofelectromagnetic communication filters.
 15. The network device of claim13, wherein each of the plurality of electromagnetic communicationfilters is at a respective one of the plurality of client ports.
 16. Thenetwork device of claim 13, wherein the plurality of electromagneticcommunication filters each comprise at least one of a Media AccessControl (MAC) filter, an Internet protocol (IP) filter, an IP filter, aTCP filter, and a UDP port filter.
 17. The network device of claim 8,wherein the networking componentry associates with each of the pluralityof client ports filter information unique to each of the plurality ofclient ports.
 18. The network device of claim 8, wherein the networkingcomponentry associates the filter information with more than one of theplurality of client ports that is the same for each of the more than oneof the plurality of client ports.